The recorder is a pipe instrument similar to the flute. It is closer to the ancient flutes than modern valved side-flutes, by consisting of a narrow long pipe with fingerholes. The unique sound of the recorder comes from its moutpiece.
The mouthpiece of the recorder is known as a fipple. This piece has a narrow slit (windway or ducted flue) which concentrates the moving air column and has two outlets. Through one outlet air flows through the body of the pipe, while through the other (the lip or labium - which produces the Bernoulli effect), it exists the instrument.
Recorders are made from many different types of materials, ranging from natural woods, to artificial materials such as plastics.
Source: http://www.miayf.org/woodwind/recorder/
4 recorders in C: Garklein, soprano, tenor, and great-bass, played by Jay C Easton.
http://www.jayeaston.com/galleries/Unusual_instruments/Unusual_p_4_recorders.html